Tens of thousands saved by building a BAM microscope out of LEGO

A Brewster Angle Microscope (BAM) can run you around $100,000. If you don’t have that lying around you could just use some LEGO pieces to build your own. Having been faced with no budget to buy the hardware, and needing the data to finish his PhD, [Matthew] figured out a way to build something passable on the cheap.

These microscopes bounce a light source off of a pool of water and into the lens of a camera. The thing is the angle of the sender and receiver must be just perfect at 53.1 degrees. [Matthew] was able to afford a used camera, and started experimenting with some lab equipment to mount the rig. But he just couldn’t get the adjustments right. Since he had to move the mounting hardware by hand it was impossible not to over or under shoot the corrections. But then he had a eureka moment. LEGO pieces have very accurate tolerances, and you can get geared and motorized parts. He leveraged the quality of the toy into a BAM whose alignment can be tweak with great precision.

It may not look like much, but you can see stearic acid floating through the microscope’s field of vision in the clip after the break. This is exactly the type of observations he needed to perform. Of course if you just need a microscope you can use a laser and a drop of water.

33 thoughts on “Tens of thousands saved by building a BAM microscope out of LEGO”

I’ll pass that comment on to my examiner, but as I have just finished writing a flipping huge thesis (188 pages) of which this is only a small part, I do hope that at least look at the other stuff! :-)

for those super precise angles that you mention you should look into sine bars. I am a prototype machinist ant an aero space firm and these inexpensive tools let you hit really precise angles look them up

As ambitious a project as it was I didn’t think it would be a rallying point for a revolution agains the establishment (of equipment manufacturers). I will make sure the next version has pitch forks and flaming torches to accommodate.

Yes we are hoping to use a better laser (non LED) to improved some of the optical issues but this presents new issues as the only ones we have are so heavy they make the frame sag. It is part of the reason we are currently making a new version with a stronger frame. However, when we get it working with the new laser I am not sure if a pinhole will give us a significantly better image.

That said it is a very easy thing to try so I will add it to our todo list and report back!

Actually, a LED-laser should do fine as long as you clean the beam. A simple microscope objective followed by a 10..20um pinhole and a collimating lens (anything that is better that the off-the-shelf-magnifying-glass) should give you a very good image. I tried this when measuring the tear-film lipid layer (a dual molecule layer).
You can reduce the beam-size with an optical stop if it is too wide.

If you are buying a new laser, just get a fiber coupled laser, or make an undergrad fiber couple the one you already have. You can move everything but the final collimation assembly off of the main stage AND single mode fiber cleans the beam like a pin hole. Once everything is coupled and aligned, fiber also makes moving stuff around so much easier.

@adcurtin. I love that idea, mirrors would make it a lot easier to mount that’s for sure. I will have to have a think about the exact details because we do have the complication that the frames can be moved back and forth from each other (to compensate for any difference in water level.

@Johan Your right, much like the mirror idea from adcurtin that would solve a number of mounting problems. We actually already have a number of fibre coupled lasers so we might be able to try this pretty quickly. I’ll talk to the keeper of our stores and see what we can dig out.

I think using a fibre based light source with a mirror directed camera would really improve streamline design. I’ll post an update when I have time to build v.3 with some of these improvements, Thanks for the feedback!

Hahaha, I thought that [Matthew] saved hundreds of thousands of people with this device, judging by the title, not hundreds of thousands of dollars. I was pretty impressed, but this is still really neat! I didn’t realized Legos were that tight in tolerances.

@Ren Just to clarify, no one over the age of 8 that doesn’t piddle their life away playing with plastic toy blocks gives a flying fuck what the plural form is.

Glad the OP got what he needed for his thesis (way back when for my PHD I built a GCMS pretty much from scratch) but the LEGO thing was a waste of time. As mentioned in other posts, building a simple rig out of metal/wood would have been easier/cheaper and way way way better.

I don’t know if your university has an engineering department, but even an second year student should be able to whip you up a quite a sturdy rig from basically scrap. I know I would.

The pricing for lab equipment is quite high, I agree with that. But looking at it from a production standpoint, the production volumes are actually pretty low (low enough to consider it single-piece or short run production and not mass production). Coupled with the fact it often involves fine mechanics with close tolerances makes for expensive fabrication and thus expensive products.

I think the mark of any good researcher is being able to work around the limitations of the equipment he can get to get valid results.

We do indeed have an engineering department full of mechanical engineering students! Sadly however I had a hard time convincing them to come build me a rig (I even tried cookies) so I was forced to rely on a building material I know and love. The end product is the best a a biochemistry student, more used to beakers of colourful chemicals, could manage :-)

However, the project (me included) is now part of the School of Engineering so I am hoping that the next version will be a vast improvement!

As I understand lab equipment is expensive because of tolerance/presicion insurance. They are PROVED to be exact. A glass beaker is not expensive because its made of glass. It’s expensive because you’re assured that your 100mL sulphuric acid is exactly 100mL and not 100,1mL.

At least that’s what I’ve understood from talking with lab techs.

On the other hand if high precision is not “the shizzle”, then yes, it’s fantastically overpriced.

I completely agree my fudged version is hopefully going to be suitable for the work we want to do, but it’s a long way (in terms of precision) from the systems made by Accurion or LOT. A simple design is often very cheap, it’s the repeatability and accuracy of an industrially designed machine that costs the big bucks!

That said it’s projects like this that I think lead to the greatest innovation in finding low cost solutions to these complex problems.